Question

I’m using hibernate 3 with c3p0 for a program which constantly extracts data from some source and writes it to a database.
Now the problem is, that the database might become unavailable for some reasons (in the simplest case: i simply shut it down).

If anything is about to be written to the database there should not be any exception – the query should wait for all eternity until the database becomes available again.
If I’m not mistaken this is one of the things the connection pool could do for me: if there is a problem with the db, just retry to connect – in the worst case for infinity.

But instead i get a broken pipe exception, sometimes followed by connection refused and then the exception is passed to my own code, which shouldn’t happen.

Even if I catch the exception, how could i cleanly reinitialize hibernate again? (So far without c3p0 i simply built the session factory again, but i wouldn’t be surprised if that could leak connections (or is it ok to do so?)).

The database is Virtuoso open source edition.

My hibernate.xml.cfg c3p0 config:

<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>  
<property name="hibernate.c3p0.breakAfterAcquireFailure">false</property>
<property name="hibernate.c3p0.acquireRetryAttempts">-1</property>
<property name="hibernate.c3p0.acquireRetryDelay">30000</property>
<property name="hibernate.c3p0.automaticTestTable">my_test_table</property>

<property name="hibernate.c3p0.initialPoolSize">3</property>
<property name="hibernate.c3p0.minPoolSize">3</property>
<property name="hibernate.c3p0.maxPoolSize">10</property>

btw: The test table is created and i get tons of debug output- so it seems it actually reads the config.

Answer 1

Well it seems that BoneCP has actually implemented this. It can be set to record the transaction and replay it upon network or database failure:

http://jolbox.com/bonecp/downloads/site/apidocs/com/jolbox/bonecp/BoneCPConfig.html#setTransactionRecoveryEnabled(boolean)